Method and apparatus for extruding hollow articles



p 1970- G. SIBLER 3,528,275

METHOD AND APPARATUS FOR EXTRUDING HOLLOW ARTICLES Filed Sept. 13, 19664 Sheets-$heet 1 INVENTOR I 617 152 SIBLER A T7012 N575 Sept. 15, 1970G. SIBLER 3,528,275

METHOD AND APPARATUS FOR EXTRUDING HOLLOW ARTICLES Filed Sept. 13, 1966'4 Shaats-Shaet ,1:

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l INVENTOR GU/VTEP' SIBLEQ ATTQRN'Y G. SIBLER METHOD AND APPARATUS FOREXTRUDING HOLLOW AfiT I CLES Filed Sept. 13, 1966 4 Sheets-Sheet 5 Lid11 u INVENTOR GU VI'ER S/BLEQ Whiz! 7 10 ATTORNEYS Sept. 15, 1970 G.SIBLER 3,528,275

METHOD AND APPARATUS FOR EXTHUDING HOLLOW ARTICLES Filed Sept. 13,.19664 Shaats-8lwut A INVENTOR 61111762 SIBLEZ United States Patent fie3,528,275 Patented Sept. 15., 1970 US. Cl. 72-256 11 Claims ABSTRACT OFTHE DISCLOSURE A method of forming metal pipes using an indirectextrusion press including a receptacle having a bore for the ingot, anextrusion ram with an indirect die arranged in alignment with one end ofthe bore of the receptacle, and a movable plunger with aninterchangeable upsetting ram or main die and a hollow plug member whichis alignable with the opposite end of the receptacle bore in conjunctionwith a piercing mandrel which is movable through the plug, comprisesinserting the ingot into the bore of the receptacle of the indirect die,closing one end and advancing the main die against the ingot to upsetit. Thereafter the upsetting ram carrying the main die is moved out ofalignment with the receptacle bore and the plug is inserted into thebore up to a location at which its inner end is spaced outwardly from aposition occupied by the inner end of the main die when it waspositioned there. Thereafter, the piercing mandrel is moved through thebore of the plug and through the upset ingot to pierce it and theindirect die and the plug are moved relatively toward each other inorder to extrude the upset ingot around the mandrel.

The apparatus for the method includes a press plunger which is locatedadjacent a movable ingot receptacle having a bore into which a press dieis movable. The press Plunger carries a pivotal arm with a plunger dieon one end and a plug having a through bore at the opposite end. Theplunger die may be moved with the press plunger or ram to upset thebillet placed in the receptacle. Thereafter, the arm may be shifted toalign the plug with the receptacle bore. The press plunger also carriesa piercing mandrel which is mounted for reciprocation through the boreof the plug to pierce the billet. After extrusion the plug is againshifted in respect to the associated plunger receptacle bore and itcarries the residue with it from the receptacle to a position in whichit may be dropped into a packing press located therebeneath. In thepacking press a plunger compresses the residue to compact it into asmall size mass which is dumped into a collecting receptacle.

SUMMARY OF THE INVENTION This invention relates, in general, to theconstruction of extrusion presses and to a method of extruding metalpipes or similar hollow bodies and, in particular, to a new and usefulextrusion press in which the billet to be extruded is first upset,thereafter pierced and finally extruded over a mandrel and to a processfor extruding metal billets.

The invention provides an indirect pressing process for the productionof metal pipes and similar hollow bodies from unpierced ingots orbillets. The indirect pressing process has the advantage of a directpressing because of the better flow behavior in the ingot duringpressing so that substantial energy saving can be achieved. Furthermore,the better flow behavior results in better metallurgical properties ofthe product. In addition, no

metal flow directed from the surface of the ingot is produced during theextrusion so that an additional advantage is achieved and that noimpurities found on the surface of the ingot can get into the core ofthe seciton to be produced. It is therefore preferred to pressindirectly with the shell.

Though the indirect pressing process yields qualitatively the bestresults, it is only rarely used. One of the reasons is that it is notposisble to produce quality pipes and similar hollow bodies in anindirect press designed according to modern standards. An indirectpressing process for the production of metal pipes is known where theunpierced ingot is first pierced and then extruded. On the basis of theconstructional design of the known press, as indicated in U.S. Pat. No.2,320,071 only those ingots can be pierced and pressed having outsidediameters which are substantially equal to the inside diameter of theingot receiving chamber or receptacle into which the ingots to bepressed are inerted under vacuum or suction conditions.

It is always difiicult to obtain ingots with correct outside dimensionsand because the mandrel moves during the piercing of the ingot, pipeswhich are produced after the initial production, will have differentwall thicknesses than will be produced during the extrusion of thepierced ingot. Even in those instances where the pressing tool canproduce the ingots and maintain the correct outside diameter, it willnever be possible to produce from the inserted ingots quality pipessince even when an ingot is inserted with suction, there is still acertain play between the outside diameter of the ingot and the insidediameter of the receptacle which enhances rather than prevents themovement of the mandrel. Thus, it is absolutely essential for theproduction of quality pipes that the ingot be first upset in theindirect pressing process just as in the direct pressing process so thatit is certain to fill the receptacle completely before it is pierced andpressed. The known indirect presses do not permit the quality productionof pipes even from the upset ingot because the ingot rises after theupsetting during the piercing and the necessary space is not availablein the known indirect presses.

In accordance with the invention, there is provided a pressing deviceand method for the production of metal pipes and similar hollow bodiesfrom unpierced ingots in a metal extrusion press which includes meansfor upsetting the ingot and to take into account the upsettingcharacteristics of the ingot during the rise thereof. In accordance withthe invention, the ingot to be formed is inserted in a receptacle and isupset therein by means of a special upsetting die which is arranged tomove into the receptacle and to upset the ingot against an indirectpress die. The main press plunger is then withdrawn and the upsettingdie is exchanged for a hollow plug which is of a size to leave a freespace in the re ceptacle between it and the upset ingot after thereceptacle is closed so that the ingot can expand unhindered during thefollowing piercing. The plug provides centering means for a piercingmandrel which moves through the plug and pierces the ingot. Thereafter,the pierced ingot is extruded over the front end of the shearing mandrelwhich is aligned with the plug and the piercing mandrel.

In the preferred arrangement, a hydraulic metal extrusion press isprovided with a tool changing mechanism which is arranged in thetravelling spar and pressure plate holder, respectively, to alternatelybring the upsetting die and the hollow plug, respectively, into thecentral press axis position. The hollow plug extends outwardly by alesser amount in the axial direction than the upsetting die.

Accordingly, it is an object of the invention to provide 3 an extrusiondevice having means for upsetting a billet to be extruded and thereafterfor piercing and extruding the same billet in the upsetting receptacle.

A further object of the invention is to provide a method of formingarticles such as metal pipes and similar hollow bodies from unpiercedingots in a metal pipe press which is provided with a piercing mandrelwhich moves independently of the main press drive and which comprisesupsetting the ingot in the receptacle by means of an upsetting dieacting between the ingot and an indirect die and thereafter removing theupsetting die and closing the receptacle with a plug which does notextend axially into the receptacle by the same amount as the upsettingdie, piercing the ingot by use of a piercing mandrel which is movedthrough an opening defined in the plug, and thereafter extruding thematerial of the ingot over the mandrel.

A further object of the invention is to provide a device for theindirect pressing of metal pipes and similar hollow bodies fromunpierced ingots which is simple in design, rugged in construction andeconomical to manufacture.

The various features of novelty which characterize the invention arepointed out with particularity in the claims annexed to and forming apart of this specification. For a better understanding of the invention,its operating advantages and specific objects attained by its use,reference should be had to the accompanying drawings and descriptivematter in which there is illustrated and described a preferredembodiment of the invention.

In the drawings:

FIG. 1 is a partial elevational and partial longitudinal sectional viewof an extrusion press constructed in accordance with the invention;

FIGS. 2 to are views similar to FIG. 1 indicating the various positionsof operation of the device in carrying out the process of the invention;and

FIG. 11 is a partial side elevational and sectional view of a portion ofthe extrusion press and a device for compressing and removing the scrapfrom the press.

Referring to the drawings, in particular, the invention embodied thereincomprises a main press drive 1 which includes a press plunger 1. Acounter holder 2 is pro vided alongside the press plunger and itoperates in association with a receptacle 3. It includes press dies 4aand 4b which may be alternately positioned for centering in respect to abore 3a of the receptacle into which they are slidable. A changingdevice (not shown) is provided for shifting a slide member 30 on theholder 2 for positioning a selected one of the indirect press dies 4a or4b in an operative position. Ingots or billets 6 are loaded into thereceptacle 3 by means of a loading mechanism generally indicated at 5.

Each indirect press die 4a and 4b contains at its front end a matirxholder 4 and a press matrix 4", as indicated in FIG. 8. The plunger 1'of the main press drive 1 includes a pressure plate 7 which is arrangedin a pressure plate holder or travelling spar 7'. A changing mechanismor carriage 8 is mounted for slidable transverse movement at the forwardend of the plunger 1. The carriage 8 carries at spaced locations aplunger die 9 and a plug 10 which may be selectively positioned inalignment with the outer end of the pressure plate 7 and aligned withthe bore 3a of the receptacle 3. The spacing between the upsetting die 9and the hollow plug 10 is selected such that the plug 10 can be easilyfreed of the adhering press residue when it is in the eccentric positiondisposed on one side of the plunger 1, for example, see FIGS. 10 and 11.With the plug 10 in the eccentric position, the upsetting die 9 wouldthen be centered with regard to the press axis.

The axial extension of the required setting die 9 is chosen inaccordance with the available volume of the ingot 6 and the size of apiercing mandrel 11. The piercing mandrel is carried at the outer end ofa shearing mandrel 14 which slides in a bore of a sleeve 32 which isaligned with a bore of the pressure plate 7.

In accordance with the invention, the carriage 8 may be shifted to alignthe plug 10 with the axis of the press. The plug 10 thus provides both apress disk and a guide for the piercing mandrel 11 and shearing mandrel14. For this latter purpose, the plug 10 is provided with a bore 10'sufficiently large enough to accommodate the shearing mandrel 14 whichis made of a slightly larger diameter than the piercing mandrel 11.

In accordance with the method of the invention, the billet 6 isdeposited within the bore 3a of the receptacle 3 when in the positionindicated in FIG. 1. At this operating position, the upsetting die 9 isarranged along the axis of the press and the press plunger 1 isindicated in the retracted end poistion. The piercing mandrel 11 and theshearing mandrel 14 are also in the retracted position.

As indicated in FIG. 2, the main press plunger 1' is advanced to theright in the direction of the arrow under low pressure and pushes theupsetting die 9 against the ingot to force it into the diameter 3a ofthe receptacle 3. The ingot loader 5 then returns to its startingposition. The ingot 6 is then partly supported by the receptacle 3 in aposition clamped between the indirect press die 4a and the upsetting die9.

As indicated in FIG. 3, the receptacle 3 is moved in the direction ofthe arrow indicated and is pressed against the pressure plate holder 7secured on the plunger 1'.

The ingot is then upset by advancing the main press plunger 1' inrespect to the receptacle in the direction of the arrow indicated inFIG. 4. The upset ingot is designated in FIG. 4 by the numeral 6'. Afterthe upsetting, the main press drive 1 is relieved and the main pressplunger 1' retracted in the direction of the arrow indicated in FIG. 5to permit the displacement of the tool carriage 8 in the direction ofthe arrow indicated to position the plug 10 in alignment with the centerof the press axis (FIG. 5).

Because of the fact that the upsetting die 9 and the plug 10 may bealternately aligned with the press axis, in accordance with theinvention, it is possible to obtain a free space within the bore 3a ofthe receptacle 3 to permit an elongation or rise of the ingot 6. Duringthe piercing as indicated in FIG. 6, the main press plunger 1 is movedforward in the direction of the arrow until the pressure plate holder 7bears tightly on the receptacle 3. The remaining free space 12 betweenthe ingot 6' and the plug 10 permits the ingot to rise freely while itis being pierced.

As indicated in FIG. 7, the piercing operation is carried out by theadvance of the mandrel 11 which moves forward along with the shearingmandrel 14. The piercing mandrel 11 pierces the ingot 6 with a piercingforce and ejects the plug 13 obtained during the piercing into thetubular interior of the indirect press dies 4a or 41). The piercingmandrel 11 is guided through the bore 10' of the hollow plug by asomewhat thicker extension or intermediate portion 14 which slides incontact with the interior of the pressure plate 7. At the end of thepiercing stroke, the mandrel shoulder of the extension 14 is alignedwith the outer edge of the plug 10. A stop 15 is provided at the outerend of the piercing mandrel 11 which abuts against a stop member orlatching device 16 when the latching elements are closed in thedirection of the arrows as indicated in FIG. 7. When the shearingmandrel portion 14 is to be extended, the latching stop members 16 aremoved out of the position indicated in FIG. 7 by spreading the membersapart as indicated by the arrows in FIG. 8.

As shown in FIG. 8, the main press plunger 1 is advanced together withthe receptacle 3 at a high pressure and presses the ingot 6' over themandrel 11 and the shearing mandrel 14 through the matrix 4 to form apipe or similar tubular body 19. After the extrusion, the main pressplunger 1' and the receptacle 3 are in the position represented in FIG.8. The press residue 18 adheres to the plug 10 at its dovetailed frontface. After the pipe 19 has been extruded, the piercing mandrel 11 isrelieved and the double latch 16 is opened. Then the pipe 19 isseparated from the press residue 18 by axial shearing by means of themandrel shoulder of the shearing mandrel 14. The piercing mandrel 11 isthen returned to its starting position in which the tip of the mandrelwill be located beyond the outer end of the plug 10, thus permitting thetransverse stroke or movement of the carriage 8. The receptacle 3 ismoved back so that the matrix holder is exposed and subsequently, themain press plunger 1' is retracted in the direction of the arrowindicated in FIG. 9 to pull the press residue 18 with the shell 18' outof the receptacle 3.

As indicated in FIG. 10, the tool carriage 8 is moved transversely inthe direction of the arrow indicated in order to position the upsettingdie 9 in the operating position in alignment with the press axis onceagain. The plug 10 with the residue 18 and the shell 18' will be locatedin the eccentric position at which it will be located over a packingpress 20 located therebeneath. A stripping cylinder 19 is arranged tomove downwardly as indicated in FIG. 11 to strip the residue from theplug 10 and to direct it into the packing press 20. The packing pressincludes a plunger 36 which is moved against the residue to compact itinto a small sized mass 6" which is dumped into a receptacle 22. Theremovad of the residue from the plug does not require any additionaldown time since the receptacle 3 is reloaded at the same time with a newingot by the loading mechanism 5.

While a specific embodiment of the invention has been shown anddescribed in detail to illustrate the application of the inventiveprinciples, it will be understood that the invention may be embodiedotherwise without departing from such principles.

What is claimed is:

1. A method of indirect stamping metal pipes and similar hollow bodiesfrom an ingot using a receptacle having a bore for the ingot, anindirect die arranged in alignment with one end of the bore of thereceptacle and a movable plunger with an interchangeable main die and ahollow plug member selectively alignable with the opposite end of thereceptacle bore, and also using a piercing mandrel which is movablethrough the bore of the plug, comprising inserting the ingot in the boreof the receptacle with the indirect die closing one end and advancingthe main die against the ingot to upset it, moving the main die out ofalignment with the receptacle bore and inserting the plug into the boreto a location at which its inner end is spaced outwardly from theposition occupied by the inner end of the main die when positioned inthe receptacle bore, moving the piercing mandrel through the bore of theplug and through the upset ingot to pierce it, and moving the indirectdie and plug relatively toward each other to extrude the upset ingotaround the mandrel.

2. A method of forming metal pipes and similar hollow bodies from aningot using a receptacle having a bore for the ingot, according to claim1, including with drawing the receptacle from around said mandrel andwithdrawing said mandrel within said plug to strip the residue from thereceptacle, and thereafter removing the residue from said plug.

3. A method of forming metal pipes and similar hollow bodies from aningot using a receptacle having a bore for the ingot, according to claim2, including positioning a new billet in the bore of the receptaclewhile the residue is being dislodged from said plug and while said maindie is being aligned with the axis of said press.

4. A device for upsetting piercing and extruding an ingot into a hollowarticle such as a pipe comprising, a movable ingot receptacle having abore defined therethrough for receiving the ingot to be formed, a mainplunger arranged adjacent one end of said receptacle bore and movabletoward and away from said receptacle, a carriage on said main plungertransversely movable in respect to said plunger, a main die on saidcarriage, a plug having a bore defined therethrough on said carriage ata spaced location from said main die, said carriage being movable toselectively position said plug and said main die in alignment with thebore of said receptacle, an indirect die arranged adjacent the other endof the bore of said receptacle, said receptacle being movable relativeto said indirect die to cause said indirect die to close one end of saidreceptacle, said plunger being movable toward said receptacle to directsaid main die against an ingot in the bore of the receptacle to upsetthe ingot, said plunger being movable away from the receptacle to bringthe main die out of the receptacle, said carriage being shiftable tomove said main die out of alignment with said receptacle and to positionsaid plug in alignment with the bore of said receptacle, a mandrelaxially slidable in said plunger and through the opening in said plug topierce the billet in said receptacle, said main die being movablerelatively toward said indirect die under pressure to extrude the upsetpierced ingot around said mandrel to form a tubular article.

5. A device for extruding pipes and similar hollow articles, accordingto claim 4, wherein said indirect die includes a mounting die carrier, aplurality of tubular die members mounted on said carrier and beingselectively alignable with the bore of said receptacle.

6. A device for extruding pipes and similar hollow articles, accordingto claim 4, including loading means for loading a billet into the boreof said receptacle.

7. A device for extruding pipes and similar hollow articles, accordingto claim 4, wherein said plug includes an outer flange with an innerrecessed rim forming a dovetailed configuration for engagement with thepress residue when said pierced ingot is being extruded, and means fordislodging the press residue from said plug after said plug has beenremoved from the bore of said receptacle.

8. A device for extruding pipes and similar hollow articles, accordingto claim 4, including stop means for limiting the movement of saidmandrel during piercing, said stop means being removable to permit saidmandrel to move after piercing said billet.

9. A device for extruding pipes and similar hollow articles, accordingto claim 8, wherein said mandrel in cludes an outer piercing mandrel,and an intermediate shearing mandrel of slightly larger diameter thansaid piercing mandrel, said indirect die including a press matrixthrough which said shearing mandrel portion extends when material isextruded through said press matrix and around said piercing mandrel.

10. A device for extruding pipes and similar hollow articles, accordingto claim 9, including means for stopping said mandrel after the piercingmandrel penetrates the ingot, said stop means being removable to permitfurther movement of said mandrel to engage in said press matrix for theextrusion of the material.

11. A device for extruding pipes and similar hollow articles, accordingto claim 4, including a residue compacting device disposed adjacent saidmovable plunger, said carriage being shiftable to place said plug withthe residue attached thereto in a position over said compacting device,and means for stripping the residue from said plug into said compactingdevice.

References Cited UNITED STATES PATENTS 976,529 11/1910 Westerman 72-2661,670,336 5/1928 Born 72-272 1,859,990 5/1932 Schlenstedt 72-2722,388,558 11/1945 Loewy 72--272 2,491,897 12/1949 Lorant 72-2733,362,208 1/ 1968 Murphy 72-265 1,948,400 2/ 1934 Schlenstedt 72-256LOWELL A. LARSON, Primary Examiner US. Cl. X.R.

